Only channels are 1 thru 8 and 9 to 11 are inop

I ve tried 2 MN700 base units and neither one will switch
to a channel higher than channel 8 when it goes higher
such as 9 or 11 the Base unit stops working and non of
the other cards change ..if I force a PCI card to say
channel 11 along with the base station I get no network
funtion .. the wireless eithernet cards are, one a belkin
highspeed wireless G and a MN 730 card ... All equipment
is new ..is there something I'm missing?. I've updated
both base stations via Microsoft update as well as the
MN730 pci card, I'm using 2 gig Hz XP machine as server
and using wide area settings as Dynamic.
Ron